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[huxley]

Hello again everybody. Right we are now at a point of either finding a cure or breaking the car for spares....This is the latest!
New crank sensor fitted....made no difference!
New Maf sensor fitted......made no difference!
 Basically to update people on here the story is like this!
2.5v6 cdx estate 1997 poor starting problems.
The car will start on the turn of the key but idles very very rough untill the car warms up. When and only when its warm will it pull away ok.
After starting,  if you try to rev it at all, you get  lots of backfiring into the airbox to the point of it moving the top part of airbox quite a lot!
I mentioned before that if you hold your hands over the maf sensor and restrict it leaving a 10pence size hole for the air to go through it will settle the idle nicely. I have since found that if i squeeze the hose going into the ICV this gives the same results!
Now before, people have mentioned that doing this cant do any better a job than the butterflys would do on there own. I beg to differ as what we are essentially seeing here is that if the airflow into the plenum is restricted before it passes any more sensors then maybe the ECU can adjust itself for the airflow/fuel conditions??
Looking at the bigger picture we are faced with i can only see that on start up the car is drawing far to much air into the plenum and the ECU cannot cope to make its adjustments. Crazy i know but what else could it be??
come on you knowledgeable lot....hit the nail on the head!

[Kevin Wood]

It sounds like it's running lean to me. Have you checked the coolant temperature sensor?

If this is reporting "hot" all the time it will disable warmup enrichment.

Failing that, I think it needs someone with a Tech 2 to look at some live data and see if anything looks odd, and what changes when you've squeezed the ICV pipe.

I'm sure it's something trivial, and not worthy of scrapping the car, but it's an odd one, for sure :-/


Kevin

Kevin

Damn! that echo's back...

[cem_devecioglu]

Agreed ..before anything visit an expert from here..

You know the names..

[huxley]

no havnt checked that sensor!! we carried out the paperclip test to find codes for maf crank sensor and immobiliser sensor (why we dont know)
changed the 2 suspects to no avail!
Trouble is the guy doesnt want to waste money on it trying to cure the "unknown"
And at the end of the day its probably worth more broken for spares than complete!

[cem_devecioglu]

Marks DTM and TheBoy have Tech2..

[Grumpy]

no havnt checked that sensor!! we carried out the paperclip test to find codes for maf crank sensor and immobiliser sensor (why we dont know)
changed the 2 suspects to no avail!
Trouble is the guy doesnt want to waste money on it trying to cure the "unknown"
And at the end of the day its probably worth more broken for spares than complete!

You might not need to spend any money if it's the CTS. This area gets
sprayed by leaking HBV''s (coolant), and leaking scuttles (rainwater).
So it may just need the electrical lead removed and corrosion cleaned
off the terminals. I've had sensor connection corrosion on many cars
and many different sensors. A bit of a clean up and it's right as rain.

Costs nothing to check and fix.

[huxley]

ok i will give that a look tomorrow.....where am i looking for the conection and what does it look like?

[albitz]

if you post your location one of the more knowledgable members may  be nearby and able to help

[huxley]

felixstowe suffolk

[eddie]

Have you ruled out an EGR leak?

eddie

[JamesV6CDX]

Is he still driving it around without and PAS?

[Grumpy]

ok i will give that a look tomorrow.....where am i looking for the conection and what does it look like?

I have the 4 pot, but I understand that the V6 has it mounted in a
a similar position. It should be at the back of your engine, near
the Dis Module (large black lump with 6 spark plug leads coming
out of it).

You should find 2 sensors. The one with the single cable will be the
temp sender for your Temp Gauge. The one you want, is the one
with 2 cables. This sends the temp to the ECU.

Perhaps someone on here with a V6 will give a more precise
location?

[vvm]

dont think its gonna be a sensor fault
if its backfiring its cos either the plug leads are on wrong or the inlet valves are open at the wrong time. valves can be down to the cam timing being out or are sticking open
does it run perfectly when its warm or is it just better than cold?

[huxley]

Have you ruled out an EGR leak?

eddie

No we havnt ruled it out as still not sure what the fault is!!

[huxley]

dont think its gonna be a sensor fault
if its backfiring its cos either the plug leads are on wrong or the inlet valves are open at the wrong time. valves can be down to the cam timing being out or are sticking open
does it run perfectly when its warm or is it just better than cold?

The plug leads are in the correct places as they have never been touched!! Yes once warm or left to idle for about 10 mins it runs great!
Just if its cold and he tries to drive off then it doesnt want to know at all!